Glare and evaluation of lightshelves

Hi Carlos,

Are you predicting glare using the DGI? if you are, there may be some errors produced by potential glare sources behind the field of view.

findglare identifies potential glare sources. then glarendx -t dgi takes these sources and calculates glare indices in a range of directions. take a look at the predicted dgi's at adjacent directions. if there is an obvious jump in dgi between adjacent directions, then you probably have a glare source behind the field of view. To fix, simply remove the offending glare source from the file output by findglare, and re-run glarendx -t dgi. if that doesn't make any sense, let me know and i'll send you a spreadsheet i developed to identify problematic glare sources.

For Greg, or whoever else might be interested, the problem is in the calculation of dgi's omega in glarendx.c. where the glare source is behind the field of view, posindex returns -1, p becomes 0 and omega is much bigger than adjacent levels. this means the glare source is artificially inflated, and the glare index jumps up.



Phillip Greenup
Specialist Engineer
Arup Australasia
Level 10, 201 Kent St
Sydney NSW 2000
Ph (02) 9320 9426
Fax (02) 9320 9321

[email protected] 18/11/2003 9:15:11 pm >>>

Hi Greg,

The pictures were generated using the fish-eye view, they
are looking from the middle of one of the long walls of the
room to the other (the expected position of the user). So I
have the window on one side of the picture and the bottom
of the room on the other.

I give the findglare both the octree and the picture name,
but I get the same results just as if specifying only the
picture. By the way, just giving findglare the octree and
direction of the view gives an error message in DR 2.0. I
have also increased the number of ambient bounces, but it
doesn't change, either.


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